1. Field of the Invention
The present invention relates generally to a photographing apparatus and method, and more particularly, to a photographing apparatus and method in which a synthesized image is obtained by synthesizing a plurality of images that correspond to a respective plurality of diaphragm values.
2. Description of the Related Art
There are conventional photographing methods of photographing a subject while opening up a diaphragm of a photographing apparatus. These conventional photographing methods are useful for capturing an image of a plurality of subjects while emphasizing one of the subjects.
When a photographing apparatus captures an image of a plurality of subjects while a diaphragm of the photographing apparatus is opened up, the subjects which are in focus appear clearly on the image as illustrated by the middle thin-lined illustration of FIG. 1, whereas the subjects which are out-of-focus appear blurry on the image as illustrated by the thick-lined illustrations on the far right side and on the far left side of FIG. 1. In this case, it may be difficult to determine the original shapes of some of the subjects on the image.
In order to address this problem with the aforementioned conventional photographing methods, a photographing method has been suggested which involves capturing a plurality of images respectively corresponding to a plurality of diaphragm values and obtaining a synthesized (i.e., combined or composite) image by synthesizing (i.e., combining) the images.
As an example of this type of synthesis-based photographing method, Japanese Patent Laid-Open Gazette No. hei 11-271838 discloses a photographing method which involves respectively performing a plurality of exposure operations using a plurality of combinations of diaphragm values and shutter speeds by pressing a shutter-release button once. Japanese Patent Laid-Open Gazette No. 2002-084444 discloses a photographing method which involves performing a photographing operation in an ordinary photographing mode and a multi-image photographing mode, respectively, and synthesizing a plurality of images obtained by the photographing operations.
Also, Japanese Patent Laid-Open Gazette No. 2003-259200 discloses a photographing method which involves determining exposure conditions based on a photographing algorithm or method other than a typical photographing algorithm or method, and synthesizing a plurality of images obtained by performing a plurality of exposure operations while slightly varying the exposure conditions from one exposure operation to another. Japanese Patent Laid-Open Gazette No. 2002-044515 discloses a photographing method in which a synthesized image having an arbitrary image data synthesis rate can be obtained by synthesizing two sets of image data respectively corresponding to two different exposure times using a multiplier.
However, in order to obtain a synthesized image having an arbitrary image data synthesis rate by synthesizing two sets of image data respectively corresponding to two different exposure times using a multiplier, the two sets of image data must be appropriately processed in pixel units, thus increasing the time taken to obtain a synthesized image. Also, a conventional photographing method which involves synthesizing a plurality of images using a typical exposure time division method is likely to produce low-quality synthesized images.